Breather valve for air compressors



June 5, 1934. B. R. SCOTT BREATHER VALVE FOR AIR COMPRESSORS Filed 001;.15 1951 2 Sheets-Sheet l 'gwuentoz dkouwq June 5, 1934.

B. R. SCOTT BREATHER VALVE FOR AIR COMPRESSORS 2 Sheets-$heet 2 FiledOct. 13. 1931 Patented June 5, 1934 S'E'TES E AT EN FFHQE This inventionrelates to air compressors, and more particularly to air compressors ofthat type having Corliss and poppet valves.

The invention has for one of its objects to increase the efficiency ofsuch compressors, to reduce to the minimum the cost of operating suchcompressors, and to reduce to the minimum the noise incident to theoperation of such compressors.

To attain the foregoing and other objects, the nature of which willappear as the description proceeds, the invention comprehends theremoving of the Corliss and poppet valves from such compressors andsubstituting therefor a single breather valve free of moving partsrequiring lubrication and mechanical operation.

The invention is hereinafter more fully described and claimed, andillustrated in the accompanying drawings, wherein:-

Figure 1 is a view partly in side elevation and partly in verticalsection illustrating the application of the breather valve to an aircompressor;

Figure 2 is a sectional view on an enlarged scale taken on the verticalplane 2-2 of Figure 1 and extending transversely through the breathervalve and a fragmentary portion of the air compressor;

Figure 3 is a sectional view on an enlarged scale taken on a verticalplane extending centrally and longitudinally through the breather 4valve and fragmentary portions of the air compressor;

Figure 4 is a bottom plan view of a fragmentary portion of one of thecaps for holding the discharge valve strips in place in the cage of thebreather valve;

Figure 5 is a top plan view of a fragmentary portion of one of the capsfor holding the intake valve strips in place in the cage of the breathervalve, and

Figure 6 is a sectional View taken on a plane extending vertically andtransversely through the cage of the breather valve.

Referring in detail to the drawings, and particularly to Figure 2, 1designates one of the intake or suction ports, 2 one of the combinedsuction and discharge ports, and 3 one of the compressed air dischargeports of an air compressor of well-known construction. The aircompressor has a cylindrical valve chamber 4 with the lower side ofwhich the intake or suction ports communicate, with the inner lateralside of which the combined suction and discharge ports communicate, andwith the upper side of which the compressed air discharge portscommunicate.

My improved breather valve is mounted within the chamber 4 and consistsof three parts, namely a body 5 and caps 13 and 14 disposed on each sideof the body 5. The body 5 has at its ends the circular heads 6 and 7 andat its middle a medial head 8.

Extending from the end heads 6 and 7 to the annular medial head 8 arethe upper and lower walls or webs 9 and 9 defining between them achamber 10 as shown in Figure 2, this chamber being open on one side ofthe valve, this opening registering with the cylinder port 2, thechamber 16 being closed at its opposite end as shown in Figure 2. Eachof the webs 9 is provided with a plurality of longitudinally extendingslots 11 extending entirely through the webs. Each of the webs 9 isprovided with a plurality of longitudinally extending slots 12 which arepreferably in staggered relation to the slots 11 in the lower web 9. Thechamber 10 defined by the webs 9 and 9 is disposed diametrically to theheads 6, 7 and 8. It will be seen from Figure 2 that the heads 6, '7 and8 of the body 5 have exterior faces conforming to the curvature of thevalve chamber 4 and fit the valve chamber 4 snugly so as to prevent anypassage of air therearound.

Applied to the upper face of the web 9 are caps 14. These caps as shownin Figure 1 are disposed between each end head 7 or 6 and the middlehead 8. The under face of the body 5 is also provided with two caps 13extending between the middle head 8 and the end heads 6 and '7respectively. The caps 14 are provided with the longitudinally extendingslots 16 which extend straight downward from the upper circular surfaceof the cap to the inner face thereof, the inner faces of the cross barswhich define these slots 16 being recessed at 20, these cross bars beingdisposed immediately over the slots 12 of the body. The cap 13 is alsoprovided with a plurality of slots 15 which register with the cross barsbetween the slots 11 as shown most clearly in Figure 2, these cross bars11* being recessed upon their under faces as at 20. It will beunderstood that the slots 11 and 15 constitute suction ports while theslots 12 and 16 constitute discharge ports. The intake ports 11 and 15are under the control of valve strips 17 which are located between thecaps 13 and the web 9 and which normally seat against the upper sides ofthese caps in position to close the suction ports 15. The dischargeports 12 and 16 are under the control of valve strips 18 which arelocated between the caps 14 and the web 9 and which normally seatagainst the upper sides of the web 9 charge ports 12.

The valve strips 1'? and 18 are made from spring steel, and areconnected each at one end to the upper face of the webs 9 and 9 by a pin19, the other end of the valve strips being free of connection with theweb and the caps 13 and 14. As before state.., the cross bars of thelower web 9 defining the slots 11 are cut away upon their under faces asat 2 these cut away portions being in the form of arcuate recesses 20 tothe end that the valve strips 17 may move upwardly during the suctionstrokes of the compressor pistons. The heads 6, 7 and 8 are providedwith seats 21 for the reception of the ends of the valve strips 17, andthe caps 14 are provided with recesses 22 for the reception of the endsor" the valve strips 18, the recesses and the pins 19 positively holdingthe valve strips against lateral or longitudinal displacement. The caps13 are provided at their lower sides with termi nal flanges 23 andintermediate flanges 24 which have curved outer edges conforming to thecurvature of the heads 6, 7 and 8 and which contact with the wall of thevalve chamber 1. The caps 14 are also provided with terminal 25 andintermediate flanges 26 which have arouate peripheries contacting withthe wall 01" the valve chamber 1. The caps 13 and 14 are secured to thecage 5 by strips 2'? which are recessed in the heads 6, 7 and 8 and inthe heads 23 and 25 and which are secured to said first heads by machinescrews 28.

The breather valve is secured against rotation within the valve chambe1, and one end of the valve chamber closed by a plate 29. The plate 29provided with a boss 30 which engages in a recess 31 formed in the head6 of the valve cage 5, is secured to the air compressor by screws 32.

The other end of the valve chamber 4 is closed by a hollow head 33 whichis secured to the air compressor by cap screws 34 and which is providedwith a tubular extension entering the adjacent passage 10 of thebreather valve to establish communication between the compressor and theinterior of the head. This head carries an unloader 35 for the breathervalve. The unloader 35 comprises a cylinder 36 secured to andcommunicating at one end with the cap. This end of the cylinder is ofconical formation, as shown at 37, to provide a seat for the conicalportion of a valve 38 slidably mounted in the cylinder. The valve isheld normally seated by a coil spring 39 positioned between the valveand the head 10 of a screw ll. The screw 41 is engaged. with the cap 42of the cylinder 36 to permit it to be adjusted to increase or decreasethe tension of the spring 39, the screw being held in adjusted positionby a nut 43 engaged therewith and contacting with the outer side of thecap. The cylinder 36 is provided with a discharge nipple 44. which whenthe valve 37 is unseated is in communication with the adjacent passage10 of the valve.

The operation of the breather valve may be stated to be asfollowsz-During the suction strokes of the pistons of the compressor,the valve strips 17 are in raised suction port uncovering position andthe valve strips 18 are in low ered or discharge port closing position,with the result that air will pass through the breather valve from theintake or suction port 1 to the combined suction and discharge port 2 ofthe compressor.

in position to close the dis- During the discharge strokes of thepistons, the valve strips 17 will be in lowered or suction port closingposition and the valve strips 18 will be in raised or discharge portuncovering position, with the result that the air will pass through thebreather valve from the combined suction and discharge port 2 to thecompressed air discharge port 3 of the compressor. The movements of thevalve strips 17 and 18 are limited by the webs 9 and 9 and the caps 13and 14. The valve strips 17 and 18 are the only moving parts of thevalve, and they do not require lubrication in order to insure theirfunctioning properly, and they function without any mechanicalconnection between them and the moving part of the compressor. It willthus be understood that the cost of oil and grease and the cost ofelectric current required by those compressors having Corliss and poppetvalves are avoided. Furthermore, the valve strips 17 and 18 during theiroperation make little or no noise as compared with the noise made by theCorliss and poppet valves. The concave lower side of the web 9 and theconcave lower sides or faces 20 of the caps 14 permit the valve strips17 and 18 to move into positions where they will fully uncover thesuction and discharge ports of the breather valve. The cage 5 and thecaps 13 and 14 are of such simple construction as to be readily cast andfinished in lathes. After these parts have been finished the valvestrips 17 and 18 may be readily applied to the cage and thereafter thecaps may be readily applied and secured to the cage.

Attention is called to the fact that in my construction, the body 5 or"the valve has one continuous longitudinally extending passage 10 extending practically from end to end of the valve and that the webs 9 and9 are longitudinally slotted, that the middle of the valve body is reinforced by the annular head 8 and that as shown in Figure 2intermediate the head 8 and separating the slots 11 from each otherthere are the transverse septums 11 and 12 The intermediate annular head8 reinforces the valve so that it will not collapse under pressure andserves also another purpose because it permits the caps to be made insections so that the cap of one section can be removed and repairedwithout disturbing the cap of the other section. The caps are alsoprovided with intermediate ribs or septums 26 as shown in Figure 3 whichdefine the ends of the longitudinally extending slots 15 and 16 in thecaps, these septums defining the two groups of valve strips and keepingthe valve strips in place. These valve strips as shown in Figure 3 restupon the septums 11 and 12 and the septums or partitions 24 and 26 restagainst the septums 11 and 12 between the ends of the valve strips, thuspreventing any leakage of air between groups of valve strips and alsoserving as a support for the grids or longitudinally extending barswhich define the slots.

By referring to Figure 2, it will be seen that the longitudinallyextending partition walls 9 and 9 provide for a seal joint between thebody and the caps which prevents any leakage around the valve.

The provision of a single longitudinally extending chamber 10 in thebody with slots extending longitudinally has a number of advantages overa construction wherein there are provided a plurality of transverselyextending chambers, because the air all enters into the one chamber,that is, the central chamber and the pressure equalizes, each valve thushaving equal access SOT to air and the same pressure. In my valve, theair goes directly into the central chamber from the suction passage 1and directly out without having to pass through a plurality of separatechambers.

Where the body of the valve is divided into a number of transverselyextending chambers, the air entering one of the chambers has to be takencare of by that one particular group of valve strips in that chamber andshould one of these valve strips in that particular chamber stick, thepressure would be greater in that one chamber which would cause frictionwhereas where there is one chamber extending the whole length of thevalve body, the air equalizes and passes out through other valve strips.

It will be noted that in my construction the valve strips 17 and 18 areeach held at one end but are free to flex upward under suction, thatwhen the suction or pressure is relieved, the strips return to theirflattened form and close the openings which they control. This makes itparticularly easy to assemble this valve as the valve strips when laidin place prior to putting on the caps remain in place and do not shiftout of place as they would do if springs were used urging these valvestrips against their seats. It will be seen that my valve is composed ofpractically three pieces, omitting from consideration the valve strips,namely the body 5 and the caps 13 and 14. This makes the valve veryreadily assembled and makes it very easy to put the valve strips inplace.

While I have described the principle of the invention, together with thestructure which I now consider the preferred embodiment thereof, it isto be understood that the structure shown is merely illustrative andthat such changes may be made, when desired, as fall within the scope ofthe invention as claimed.

What is claimed is:-

l. A breather valve circular in cross section and comprising a bodyhavin flat opposed faces and upper and lower caps segmental in crosssection adapted to rest flat upon the faces to complete the valve, thebody having a single longitudinally extending chamber closed at bothends and at one side face of the body but opening upon the opposite sideface of the body, the upper wall of the chamber having longitudinallyextending slots defined by longitudinally extending bars, the lower wallof the chamber having longitudinally extending slots defined bylongitudinal bars, the outer faces of the last named bars being abovethe general level of the lower wall, an upper cap having longitudinallyextending slots registering with the cross bars of the upper wall anddefined by bars disposed between the slots, said bars being cut away ontheir lower faces, a lower cap having slots registering with the crossbars of the lower wall and valve strips disposed over the slots in thelast named cap and over the slots in the upper wall of the body.

2. A breather valve comprising a body having fiat upper and lower facesand provided at its ends and intermediate its ends with circular headsand upper and lower caps segmental in cross section adapted to rest flatagainst the faces and be disposed between said heads to thus completethe valve, said body having a single longitudinally extending chamberclosed on one side wall of each chamber between theintermediate head andthe end heads having longitudinally extending slots defined bylongitudinal bars and staggered with relation to the slots in the upperwall, the outer faces of the last named bars being recessed above thegeneral level of the lower face of the wall, the upper cap havinglongitudinally extending slots registering with the cross bars of theupper wall of the body and vertically extending cross bars defining saidslots and extending vertically upward to the upper face of the cap, saidcross bars being cut away on their lower faces, and resilient valvestrips disposed over the slots in the lower cap and normally restingupon the cross bars of said cap, and valve strips disposed over theslots in the upper wall of the chamber and. resting upon the cross barsdefining said slots.

3. A breather valve comprising a body having fiat upper and lower facesand provided at its ends and at its middle with circular heads and upperand lower caps segmental in cross section adapted to rest flat againstthe faces and be disposed between said heads to thus complete the valve,said body hav ng a longitudinally extending chamber closed on one sideof the body but opening upon the opposite face of the body, the upperwall of said chamber having longitudinally extending slots defined bylongitudinally extending cross bars, the lower wall of said chamherhaving longitudinally extending slots de fined by longitudinal bars andstaggered with relation to the slots in the upper wall, the outer facesof the last named bars being recessed above the general level of thelower face of the wall, the upper caps having longitudinally extendingslots registering with the bars of the upper wall of the body andvertically extending bars defining said slots and extending verticallyupward to the upper face of the cap, said bars being cut away on theirlower faces, and resilient valve strips disposed over the slots in theupper caps and normally resting upon the cross bars of said upper caps,and valve strips disposed over the slots in the upper wall of thechamber and resting upon the cross bars defining said slots, said stripsbeing retained against outward movement at their ends whereby the middleportion of each strip may bow upward to permit the inlet or discharge ofair.

4. A breather valve circular in cross section and comprising a bodyhaving flat opposed faces, the body having a single longitudinallyextending chamber closed at both ends and at one side face of the bodybut opening upon the opposite side face of the body, the body havingcircular end heads and a circular medial head through which the chamberin the body extends, the upper wall of the chamber having a plurality ofsets of longitudinally extending slots divided by transversely extendingseptums, the lower wall of the chamber having a plurality oflongitudinally extending sets of slots divided by transversely extendingseptunis, the longitudinally extending bars defined by said slots of thelower wall being cut away on their lower faces, a plurality of uppercaps adapted to be disposed between the intermediate head and the endheads,

each upper cap having a. plurality of sets of longitudinally extendingslots defined by longitudinally extending bars, the sets of slots beingseparated by a transversely extending partition adapted to register withand bear against the corresponding septum of the body, thelongitudinally extending bars defining the slots of the upper cap beingcut away upon their lower faces, a plurality of lower caps adapted to bedisposed between the intermediate head and the end heads of the body andhaving longitudinally extending slots defined by longitudinallyextending bars, the slots being divided into two sets by a transverselyextending partition registering With and resting against thecorresponding septum dividing the slots of the lower wall of the body,the slots of the lower cap registering with the longitudinal bars of thelower wall of the body and valve strips disposed over the slots in thelast named caps and over the slots in the upper wall of the body.

5. A breather valve circular in cross section and comprising a bodyhaving opposed upper and lower flat longitudinally slotted faces, thebody having a single longitudinally extending chamber closed at bothends and at one side of the body but opening upon the opposite side faceof the body, upper and lower caps detachably mounted upon the flatopposed faces of the body and having longitudinally extending slotsstaggered with relation to the slots in the body, valve strips disposedin register over the upper slots of the body and valve strips disposedin register with the slots in the lower cap, the caps extending over thevalve strips.

6. A breather valve comprising a body having opposed upper and lowerflat faces, each face being formed with a plurality of sets oflongitudinal slots divided by transversely extending septurns, upper andlower caps detachably mounted upon the flat opposed faces of the bodyand each having a plurality of series of longitudinal slots, the severalseries being separated by transversely extending septums, the septums ofthe caps engaging against the septums of the body, upper valve stripsdisposed in register with the upper slots in the body and lower valvestrips disposed in register with the slots in the lower cap, said capsextending over the valve strips.

BERT R. SCOTT.

